Michael Clarke struck a sublime century to become his country's highest Test run-scorer in a calendar year as Australia marched to an imperious 284-run lead at the close of day two of the second Test against Sri Lanka on Thursday. 

The Australia skipper, enjoying an inspired 2012, surpassed the 1,544 runs Ricky Ponting amassed in 2005 during his innings of 106, before tail-ender Mitchell Johnson rubbed salt into Sri Lanka's wounds with an unbeaten 73.

Paceman Johnson strode off at stumps with Nathan Lyon yet to score, with Australia having added 108 runs in the session after tea to drive their total to an imposing 440-8 at the Melbourne Cricket Ground.

“As many runs tomorrow would be very handy,” Clarke told reporters after celebrating his first ton at the MCG.

“I would love to see Mitchell get his second Test hundred and then we'll be back out there bowling and hopefully we can bowl Sri Lanka out.”

Sri Lanka, skittled for 156 on day one, had only a six-run lead to protect at the start of the day's play and their hopes of restricting the hosts diminished with a hamstring injury to seamer Chanaka Welegedera in the morning session.

The remaining bowlers had little assistance from a flattening pitch on a gusty day and were put to the sword by Clarke and Shane Watson, who composed a record-breaking fourth-wicket stand of 194 against Sri Lanka at the MCG.

Clarke's fifth Test ton of the year, the 22nd of his career, propelled him to 1,595 runs for the year and fourth on the all-time list behind Mohammad Yousuf (1,788), Viv Richards (1,710) and Graeme Smith (1,656).

Clarke's selection appeared a gamble after he sustained a hamstring injury in the first-Test victory in Hobart, and pundits complained that it was a case of double-standards given injury-free seamer Mitchell Starc was left out as part of the team's controversial rotation policy.  Few would be arguing after Thursday, with Clarke's 14-boundary knock confounding the Sri Lankans for more than four hours and putting Australia in the box seat to take a winning 2-0 series lead before the final Test in Sydney.